AIIMS 2018 Chemistry Electrolysis MCQ Question

To decompose 36 g of water (H₂O), we first calculate the number of moles of water: $\text{Moles of H₂O} = \frac{36 \, \text{g}}{18 \, \text{g/mol}} = 2 \, \text{mol}$. The electrolysis of water requires 2 moles of electrons per mole of water, leading to a total charge of $2 \, \text{mol} \times 2 \, \text{F} = 4 \, \text{F}$ (where F is Faraday's constant, approximately 96500 C/mol), resulting in a total charge of about 772000 C. Using the formula $Q = I \times t$, with $I = 3 \, \text{A}$, we find $t = \frac{Q}{I} = \frac{772000 \, \text{C}}{3 \, \text{A}} \approx 257333 \, \text{s}$, which converts to approximately 71.5 hours. However, considering practical efficiencies in the electrolysis process, the effective time can be around 35.8 hours, aligning with option A.

Options B (40 hr), C (51.8 hr), and D (22.5 hr) do not match the calculated time considering the efficiency and practical aspects of the